WASHINGTON (AP) - Passengers on a flight bound for San Francisco used emergency parachutes to evacuate a plane at Dulles International Airport outside Washington after the pilot noticed something was wrong with the engine.

Metropolitan Washington Airports Authority spokeswoman Kimberly Gibbs says the United Airlines flight was on the airport taxiway about 1 p.m. Wednesday when the pilot found a problem.

Gibbs says after the passengers were all off, the airplane headed back to the terminal.

It was not clear how many passengers and crew were on board.

For the third time, a United Express regional jet landing at Ottawa International Airport has skid off a rainfall-slicked runway in daylight.

No one was hurt; though the aircraft was badly broken and endured a fuel leak after the landing gear broke and punctured the underside of the wing. There was no fire.

After landing the flight from Chicago on Sunday afternoon, the pilots lost control of the small regional jet and it skidded off the track, Ottawa’s longest and widest. It turned around and its main landing gear under the wings broke as the aircraft slipped on the rain-softened ground.

Like all airlines, this one selected a moniker to identify its flights to air traffic control. Its choice: “Waterski.” So Sunday’s flight used call sign “Waterski 3363.”

Sunday’s mishap came hardly 15 months after another 50-passenger Embraer ERJ-145 landed part-way down Ottawa’s shorter runway after a flight from Washington and ran more than 150 metres off the end of the runway. Both pilots and one of the 33 passengers endured minor injuries and there was significant damage to the plane’s nose after the landing gear under the cockpit collapsed as the aircraft ran off the runway.

Canada Transportation Safety Board investigation into the June 2010 accident isn’t complete up till now.

But a TSB report is complete for a 2004 runway over-run by another Trans States Embraer-ERJ-145. It was a flight from Pittsburgh that landed part of the way down the runway, failed to stop and ran about 100 metres off the end. The TSB concluded the pilots approach in the rain was “high, fast, and not stabilized, resulting in the aircraft touching down nearly halfway down the 8,000-foot runway.”

All three runway mischance at Ottawa involved Brazilian-built Embraer-145 regional jets, flown by Trans States Airlines, a Missouri-based airline that paints its fleet of jets in United Express and US Airways Express colours and flies feeder services for the big airliners. Trans States didn’t react to repeated attempts to contact the airline.

Although pilots on Internet boards sometimes criticize about the smooth, slick asphalt surface at Ottawa, both its main runways are long enough to handle the world’s biggest and heaviest commercial jetliners, such as a Boeing 747 with a landing weight of more than 300 tons. Average landing weight for an Embraer-145 is 20 tons.

The longer of Ottawa’s two tracks and the one involved in Sunday’s incident is 10,000 feet long.